Study Says Space Makes the Heart Grow Rounder

New research suggests that astronauts' hearts grow rounder while they are in space, suggesting that spending lots of time in microgravity could lead to heart problems. That could mean trouble for people who want to embark on long-term missions to Mars. The data presented at an American College of Cardiology meeting in Washington was based on 12 astronauts who had ultrasounds while in space. Their hearts grew 9.4 percent more spherical in ...